From https://twitter.com/b0rk/status/1312413117436104705 :

> TIL that you can use the "DEBUG" trap to step through a bash script line by line

  trap '(read -p "[$BASH_SOURCE:$LINENO] $BASH_COMMAND?")' DEBUG

> [...] it does something very different than sh -x — sh -x will just print out lines, this stops before* every single line and lets you confirm that you want to run that line*

>> you can also customize the prompt with set -x

  export PS4='+(${BASH_SOURCE}:${LINENO}) '
  set -x

With a markdown_escape function, could this make for something like a notebook with ```bash fenced code blocks with syntax highlighting?